Insecticidal and repellent activity of three Satureja species against adult red flour beetles, Tribolium castaneum (Coleoptera: Tenebrionidae)

Abstract

Grains and milling products constitute a major part of the daily diet of human and animal. The primary factor in grains and by products losses is the depredation of stored-product beetles. The objective of this trial was the evaluation of insecticidal and repellent activity of essential oils (EOs) from three Satureja spp (S. khuzestanica, S. rechingeri and S. bachtiarica) which grow wild in Iran, against the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae), known as one of the most common stored-product pests worldwide. MethodologyEOs were extracted from aerial parts of three Satureja spp using a Clevenger type apparatus. Their chemical compositions were analyzed by gas chromatography–mass spectrometry (GC/MS). ResultsResults indicated that phenolic compounds, such as thymol and carvacrol, are the main constituents of the EOs. Insecticidal activity on the T. castaneum adult was evaluated by direct contact and fumigation bioassays. S. khuzestanica EO was the most efficient with the lowest estimated LD50 and LC50 as 20.11μg/adult 2.51mg/L air, respectively. All the tested EOs were strongly repellent to the T. castaneum adult at the tested concentration (1% v/v). Similarly, S. khuzestanica oil at 1% (v/v) showed the highest repellent activity (98% to 100%) after 4h of exposure. ConclusionConsidering the potential toxicity and repellency of the mentioned Satureja spp EOs to the red flour beetle, future studies could investigate the practical application of this potential bio-insecticide for the control of this pest.